It is commonplace in the construction of buildings including booth industrial or commercial buildings and residential houses to install batt or particulate insulation between the ceiling joists of the house attic. However, problems may arise if the insulation is installed around the perimeter of the attic between the ceiling joists and the overlying roof deck to such an extent that air vents are blocked. Building codes in most jurisdictions presently require a free flow of ventilating air above the insulating material in order to cool the attic space during the summer months and restrict moisture buildup in the winter.
Soffit or eave vents are currently the most common type of residential attic ventilation. Such vents are intended to provide free flow of air through the opening between the top wall plate of the house and the underside of the roof deck. Ventilating air can circulate into and out of the attic cavity provided that this passageway remains unobstructed.
It is known to provide a cardboard baffle which can be installed between adjacent roof rafters to regulate the flow of ventilating air into and out of the attic.